Billy keeps up his hunting. One night, however, his dogs tree a mountain lion. Old Dan howls defiantly, and the big cat attacks. The two dogs and the mountain lion fight evenly for a while, but then Billy sees Little Ann receive a sharp wound to the shoulder. He rushes in with his axe. A moment later, knocked to the ground, the big cat is about to pounce on him, when his two dogs jump up as one and save Billy. Getting back up, Billy drives a powerful wound in the mountain lion's back. Eventually, the mountain lion dies, with both of the dogs hanging limply from its throat, their jaws clamped down on its jugular.
Little Ann only has her shoulder wound, but Old Dan is hurt all over. Billy cries, and uses the dog's blood to make mud which he uses to fill up the deep cuts long enough to get the dog home. Walking home, he hears Little Ann whimper. Old Dan has fallen behind; his innards have fallen out and snagged on a bush. Billy carefully pushes them back into his body.
When they finally return home, his mama runs the dog's entrails through water, but it is not enough. The dog dies, and Billy is crushed. He buries Old Dan on a high hill overlooking the valley. In a few days, it is clear that Little Ann has lost her will to live. She dies too, and he buries her next to Old Dan. Billy is heartbroken; he says that God is not fair. Billy's papa tries to tell him that it is all for the best, because with the money Billy has earned, the family hopes to move to town. Billy does not completely recover until on the day of the move, when he goes to visit the dogs' graves and finds a giant red fern. According to Indian legend, only an angel can plant a red fern. Billy and his family look at the fern in awe. They leave him, and while he is looking at the fern he makes peace with the fact that his dogs have died.
The end of the book is gruesome. The ghastliness of the death of Ruben, and the violence that fills the book, prepare the reader for the end. Also, it is not surprising that Rawls makes the ending extremely moving. The reader has read about the entire life of the dogs, from when they were pups until their death. We have seen all of the characters, even mama, even the competitors at the championship coon hunt, grow fond of the dogs.
Also, the death of the dogs only reinforces our feelings of admiration for them. They do not die because they made a mistake, but because they bravely faced a mountain lion. Rawls includes many heroic actions in the fight. It is important to remember the beginning of the story, when Billy and his hounds heard the mountain lion's call from their cave. Now, the story has come full circle, and the dogs have defeated the lion.
Little Ann's death also reinforces the idea that these two dogs are special. She has such a close, strong bond with Old Dan that she cannot live without him.
The red fern helps Billy understand why his dogs are gone. His father believes in fate, that everything happens for a reason. When Billy sees the red fern and knows that an angel must have planted it, he begins to think that maybe his dogs were part of a higher purpose. It is important to remember all the times in the book when Billy prayed for his dogs, and they survived. Within the context of the book, religion has certainly played a large role in the lives and deaths of the dogs.